(1) Field of the Invention
The present invention relates to an apparatus for indicating and signalling to a user of a cooking vessel a specific operating condition of the cooking vessel. More particularly, the present invention relates to an apparatus for signalling an operating condition, such as the temperature or pressure in a cooking vessel, by an optical or acoustical signal which can be perceived by the user of the cooking vessel at a remote distance. More specifically, the present invention relates to an apparatus for signalling an operating condition of a cooking vessel by detecting the movement of an indicating element relative to a measurement scale of a thermometer or pressure gauge at a specified point on the thermometer or pressure gauge display.
(2) State of the Prior Art
Devices are known for the electrical signalling and display of boiling temperatures, for instance from DE-OS 29 09 129. A knob of the lid of the cooking vessel of this specification has on its outer peripheral surface at least two contact rings insulated from one another. As a function of the cover temperature, an electrical circuit for generating a signal is closed by a switch. This is arranged in the lid knob by means of a contact device which can be mounted with the contact rings and a power supply and display unit. The switch is designed as a Hall switch, and an indicator of a bimetal spiral has a magnet. This known device assumes that the conductors have good contacts. Furthermore, a structural change to the already existing thermometers, for example the installation of magnets and contact rings, is required in order to be able to signal a specific operating state, such as a specific temperature having been reached for the purpose of switching a heat source to a lower temperature level for the remaining cooking time.